I drink a TON of pop. Tons. Seriously, I probably go though at least 4 cases or so a week. Hell, my office at work (my actual office, not the company or floor or building) has vending machine just for me, and I fill that at least 2x a week. Seriously, the thing is like 30 inchesfrom my desk. (One of the maytag skyboxs) Until 2 years ago, that was all regular, generally Coke & Mountain Dew. I made a resolution to switch to diet, and I did.
2 years later, with the same, if not higher pop intake, and I have lost exactly zero weight. Granted at that time I was throwing freight around for 10-12 hours a day, probably burning around 4000 cals a day (I actually lost weight, ~15 or so lbs, drinking all that regular pop, which the pop amounted to over 2000 cals a day plus breakfast, lunch, a bag of chips or a polish for a 'snack', and dinner ). Now I really just type all day except on the weekends.